Striking mechanisms for sound production



* y 1970 G. o. SJOSTRAND ,4

STRIKING MECHANISMS FOR SOUND PRODUCTION Filed 001.- 9, 1967 I 4 r K a FIG.I.

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z? 7% in! MM i INVENTOR GUNNAR OLOF SJOSTRAND ATTORNEY United States Patent ()lfice US. Cl. 84-243 2 Claims ABSTRACT OF THE DISCLOSURE A striking mechanism for musical instruments in which a string or like sounding element is struck by means of a hammer which with the aid of a key or means actuated by a key is movable toward the string. In this mechanism the hammer is connected to the key or the like by resilient means which, when the movement of the key is stopped by abutment means, permits the hammer to continue its movement toward the string to strike it, but which by its being engaged with an engagement surface provided on the key prevents the hammer from performing a timeconsuming reverse pivotment at the return.

This invention relates to a striking mechanism comprising a key or like member which is adapted, directly or via transmission means, to strike a string, rod or like element by means of a hammer.

Striking mechanisms of e.g. pianos and like musical instrumentsever since the first striking mechanism was constructed more than 250 years ago-have incorporated rigid means pivoted to shafts or adapted for pivotment over so-called balance rails. However, no elastic or resilient materials have been utilized hitherto for such means.

To make for a quicker repetition and greater dynamic sensitivity the number of movable parts has been enlarged, like in the Prell-mechanism constructed by Job. Andr. Stein and including a release device.

In certain cases, hammers secured to springs have been employed to strike metal rods or sounding spring steel. The springs were allowed to swing freely or in a known case they were braked by an abutment provided in the instrument. However, in each case the spring at the abutment had first applied to it a rearward spring back movement away from the sounding element. This delayed the striking movement and reduced the possible repetition speed. In the cases where an abutment was employed to brake the striking movement, the abutment being independent in point of movement of that of the key, the spring had to elfect an unnecessarily large stroke, which in turn reduced the repetition speed obtainable. A mechanism of the last mentioned type is entirely inconceivable in connection with pianos, grand pianos and similar musical instruments.

The object of the present invention is to provide a mechanism which in a simple way permits a considerable increase of the repetition speed and a very rapid removal of the hammer from the string or like element. The striking mechanism according to the invention is characterised 3,512,442 Patented May 19, 1970 in that a resilient tongue or like member has one end attached to and spaced from the free end of the key or the means swingable or shiftable by said key, that the tongue extends along the free end of said key or said means, has its opposite end slightly projecting beyond said free end of said key or said means and at said slightly projecting end carries the hammer, that the face of said key or said means turned toward-s the tongue presents a curved bevel at the inner end, and that said face of said key or said means as well as the bevelled portion thereof are preferably provided with a sound damping coating.

The above features of the invention will become apparent from the following specification in which one embodiment, chosen by way of example, of the striking mechanism is described with reference to the accompanying drawing in which:

FIGS. 1-3 show side views of a highly schematic key mechanism in three different positions during a striking cycle.

In the drawing, 1 denotes the key which is a rigid body and is pivotal over the balance rail 5 towards the keybed 7. The key is laterally guided by the two guide pins 6. The key hammer is denoted 3 and the string which the hammer is adapted to strike, is denoted 4.

According to the invention, a tongue 2 of resilient material is attached to and spaced from the inner end of the key 1. At the face of the key turned towards said tongue 2 a bevel 9 is provided at said inner end of the key 1. A sound damping coating 8 is arranged along said bevel 9 as well as along at least part of that portion of the upper surface of the key 1, which is turned towards the tongue 2.

In FIG. 1 the key is at rest and the tongue is not actuated.

By reason of the resilient tongue 2 having a large part of its length applied against the key or the means set in motion by the key, no delaying rearward spring back movement of the hammer will occur when the key is struck, but the hammer will immediately be accelerated towards the string. When the key 1 or corresponding means is stopped by the keybed 7 or similar means the hammer is thrown towards and strikes the string. By the key end having the bevelled portion formed thereon the subsequent return movement of the spring will be braked without any undesired aftervibration. The described arrangement will provide an efiicient power transmission to the hammer and an extremely rapid function. With the use of the striking mechanism according to the invention the repetition speed can be increased so much as to exceed by far the physiologically possible human capacity which is capable of 10 repetitions per second. As the resilient tongue greatly reduces the period the hammer is in contact with the string, thereby satisfying the requirement that the hammer shall leave the string within a unit time corresponding to the highest frequency of the tone source, an improved tonal splendour will be obtained with the use of the mechanism according to the invention.

What I claim and desire to secure by Letters Patent is:

1. A striking mechanism comprising a tuned sound generating element,

a swingably mounted actuating means constituted by a rigid arm swingable around a transversely extending axis located at a distance from one end of said arm,

a resilient tongue having one end secured to said rigid arm between said transverse axis and the said one end of said arm and extending along said arm toward the said one end of said arm,

a hammer carried by said tongue and secured to the end of said tongue opposite to the end of said tongue secured to said arm,

and a face of said arm turned toward said tongue having a sound damping coating thereon,

said tongue having the length of the portion of said tongue extending along said arm essentially equal to the total length of said tongue.

2. The striking mechanism of claim 4 wherein said face of said arm turned toward said tongue presents a curved beveled surface toward said tongue.

References Cited UNITED STATES PATENTS 2,159,491 5/1939 Rose 84-404 2,964,988 12/1960 Merchant 84-404 RICHARD B. WILKINSON, Primary Examiner 10 L. R. FRANKLIN, Assistant Examiner US. Cl. X.-R. 

